Manual Reference Pages - AFNIX::SEC (3)

CONTENTS

The Standard Securitymodule is an original implementation of several standards and techniques used in the field of cryptography. The module provides the objects than enables message hashing, symetric and assymetric ciphers and digital signature computation. The implementation follows the recommendation from NIST and PKCS and the standard reference that it implements is always attached to the underlying object.

Hash objects
Hashing is the ability to generate an almostunique representation from a string. Although, there is no guarantee that two different string will not produce the same result -- known as a collision -- the sophistication of the hashing function attempt to minimize such eventuality. The hashing process is not reversible. There are several hashing functions available in the public domain. To name a few, MD5 is the message digest 5, and SHA is the secure hash algorithm. The following table illustrates the size of the result with different hashing functions.

Function

Result size

MD-2

128 bits

MD-4

128 bits

MD-5

128 bits

SHA-1

160 bits

SHA-224

224 bits

SHA-256

256 bits

SHA-384

384 bits

SHA-512

512 bits

Hasher object
The Hasherclass is a text hashing computation class. The class computes a hash value from a literal object, a buffer or an input stream. Once computed, the hash value is stored as an array of bytes that can be retrieved one by one or at all in the form of a string representation.

Creating a hasher
Several hasher objects are available in the module. For example, the Md5object is the hasher object that implements the MD-5 algorithm. The constructor does not take any argument.

The computemethod computes the hash value. For example, the string "abc" returns the value "900150983CD24FB0D6963F7D28E17F72"which is 16 bytes long.

const hval (md:compute "abc")

Creating a SHA hasher
There are several SHA objects that produces results of different size as indicated in the next table.

Hasher

Size

Constructor

SHA-1

160 bits

Sha1

SHA-224

224 bits

Sha224

SHA-256

256 bits

Sha256

SHA-384

384 bits

Sha384

SHA-512

512 bits

Sha512

The computemethod computes the hash value. For example, the string "abc" returns with SHA-1 the 20 bytes long value:
"A9993E364706816ABA3E25717850C26C9CD0D89D"

Cipher key principles
Cipher key management is an important concept in the ciphering land. In a simple mode, a key is used by a cipher to encode some data. Although the key can be any sequence of bytes, it is preferable to have the key built from a specific source such like a pass-phrase. A cipher key comes basically into two flavors: keys for symmetric ciphers and keys for asymmetric ciphers. A key for a symmetric cipher is easy to derive and generally follows a standard process which is independent of the cipher itself. A key for an asymmetric cipher is more complex to derive and is generally dependent on the cipher itself.

Key operations
The basic operations associated with a key are the key identification by type and size. The key type is an item that identifies the key nature. The get-typemethod returns the key type as specified by the table below.

Key

Description

KSYM

Symmetric cipher key

KRSA

Asymmetric RSA cipher key

KMAC

Message authentication key

KDSA

Message signature key

The message authentication key as represented by the KMACsymbol is similar to the symmetric key. The key type can be obtained with the get-typemethod.

# get the key type
const type (key:get-type)

The key size is the canonical size as specified by the key or the cipher specification. The get-bitsreturns the key size in bits. The get-sizereturns the key size in bytes rounded to the nearest value. The table below describes the nature of the key size returned.

Key

Type

Description

KSYM

byte

Byte array size

KRSA

bits

Modulus size

KMAC

byte

Byte array size

KDSA

bits

Signature size

const bits (key:get-bits)
const size (key:get-size)

Key representation
Unfortunately, it is not easy to represent a key, since the representation depends on the keys type. For example, a symmetric key can be formatted as a simple octet string. On the other hand, a RSA key has two components; namely the modulus and the exponent, which needs to be distinguished and therefore making the representation more difficult. Other cipher keys are even more complicated. For this reason, the representation model is a relaxed one. The formatmethod can be called without argument to obtain an unique octet string representation if this representation is possible. If the key representation requires some parameters, the format method may accept one or several arguments to distinguish the key components.

There are other key representations. The natural one is the byte representation for a symmetric key, while a number based representation is generally more convenient with asymmetric keys. The get-bytemethod returns a key byte by index if possible. The get-relatif-keyreturns a key value by relatif number if possible.

Symmetric cipher key

Creating a symmetric cipher key
The Keyclass can be used to create a cipher key suitable for a symmetric cipher. By default a 128 bits random key is generated, but the key can be also generated from an octet string.

const key (afnix:sec:Key)
assert true (afnix:sec:key-p key)

The constructor also supports the use of an octet string representation of the key.

Symmetric key functions
The basic operation associated with a symmetric key is the byte extraction. The get-sizemethod can be used to determine the byte key size. Once the key size has been obtained, the key byte can be accessed by index with the get-bytemethod.

Asymmetric cipher key
An asymmetric cipher key can be generated for a particular asymmetric cipher, such like RSA. Generally, the key contains several components identified as the public and secret key components. These components are highly dependent on the cipher type. Under some circumstances, all components might not be available.

Creating an asymmetric cipher key
The Keyclass can be used to create a specific asymmetric cipher key. Generally, the key is created by type and and bits size.

An asymmetric cipher key constructor is extremely dependent on the cipher type. For this reason, there is no constructor that can operate with a pass-phrase.

Asymmetric key functions
The basic operation associated with a asymmetric key is the relatif based representation which is generally available for all key components. For example, in the case of the RSA cipher, the modulus, the public and secret exponents can be obtained in a relatif number based representation with the help of the get-relatif-keymethod.

Creating a message authentication key
The Keyclass can also be used to create a message authentication key suitable for a message authentication code generator or validator. By default a 128 bits random key is generated, but the key can be also generated from an octet string.

Message authentication key functions
The basic operation associated with a message authentication key is the byte extraction. The get-sizemethod can be used to determine the byte key size. Once the key size has been obtained, the key byte can be accessed by index with the get-bytemethod.

Signature key functions
The basic operation associated with a signature key is the relatif based representation which is generally available for all key components. For example, in the case of the DSA signer, the prime numbers, the public and secret components can be obtained in a relatif number based representation with the help of the get-relatif-keymethod.

Stream cipher
A stream cipher is an object that encodes an input stream into an output stream. The data are read from the input stream, encoded and transmitted onto the output stream. There are basically two types of stream ciphers known as symmetric cipher and asymmetric cipher.

Symmetric cipher
A symmetric cipher is a cipher that encodes and decode data with the same key. Normally, the key is kept secret, and the data are encoded by block. For this reason, symmetric cipher are also called block cipher. In normal mode, a symmetric cipher is created with key and the data are encoded from an input stream as long as they are available. The block size depends on the nature of the cipher. As of today, the recommended symmetric cipher is the Advanced Encryption Standardor AES, also known as Rijndael.

Asymmetric cipher
An asymmetric cipher is a cipher that encodes and decode data with two keys. Normally, the data are encoded with a public key and decoded with a private key. In this model, anybody can encode a data stream, but only one person can read them. Obviously, the model can be reverse to operate in a kind of signature mode, where only one person can encode the data stream and anybody can read them. Asymmetric cipher are particularly useful when operating on unsecured channels. In this model, one end can send its public key as a mean for other people to crypt data that can only be read by the sender who is supposed to have the private key. As of today, the recommended asymmetric ciphers are RSA and DH.

Serial cipher
A serial cipher is a cipher that encodes and decode data on a byte basis. Normally, the data are encoded and decoded with the same key, thus making the symmetric cipher key, the ideal candidate for a serial cipher key. Since the data is encoded on a byte basis, it can be used efficiently with a stream. However, the serial cipher does not define a block size and therefore require some mechanism to prevent a buffer overrun when reading bytes from a stream. For this reason, the serial cipher defines a default serial block sizethat can be used to buffer the stream data. A method is provided in the class to control the buffer size and is by default set to 4Kib bytes.

Cipher base class
The Cipherbase class is an abstract class that supports the symmetric, asymmetric and serial cipher models. A cipher object has a name and is bound to a key that is used by the cipher. The class provides some base methods that can be used to retrieve some information about the cipher. The get-namemethod returns the cipher name. The set-keyand get-keymethods are both used to set or retrieve the cipher key.
The cipher operating mode can be found with the get-reversemethod. If the get-reversemethod returns true, the cipher is operating in decoding mode. Note that a set-reversemethod also exists.

Block cipher
A block cipher is an object that encodes an input stream with a symmetric cipher bound to a unique key. Since a block cipher is symmetric, the data can be coded and later decoded to their original form. The difference with the Cipherbase class is that the BlockCipherclass provides a get-block-sizemethod which returns the cipher block size.

Block Cipher base
The BlockCipherclass is a base class for the block cipher engine. The class implements the streammethod that reads from an input stream and write into an output stream. The BlockCipherclass is an abstract class and cannot be instantiated by itself. The object is actually created by using a cipher algorithm class such like the Aesclass.

trans count (cipher:stream os is)

The streammethod returns the number of characters that have been encoded. Care should be taken that most of the stream cipher operates by block and therefore, will block until a complete block has been read from the input stream, unless the end of stream is read. The block cipher is always associated with a padding scheme. By default, the NIST 800-38A recommendation is associated with the block cipher, but can be changed with the set-padding-mode.

Creating a block cipher
A BlockCipherobject can be created with a cipher constructor. As of today, the Advanced Encryption Standardor AES is the recommended symmetric cipher. The Aesclass creates a new block cipher that conforms to the AES standard.

const cipher (afnix:sec:Aes)

A block cipher can be created with a key and eventually a reverse flag. With one argument, the block cipher key is associated with the cipher. Such key can be created as indicated in the previous section. The reverse flag is used to determine if the cipher operate in encoding or decoding mode. By default, the cipher operates in coding mode.

Block cipher information
The BlockCipherclass is derived from the Cipherclass and contains several methods that provide information about the cipher. This include the cipher block size with the get-block-sizemethod.

println (aes:get-block-size)

Input cipher
In the presence of a Cipherobject, it is difficult to read an input stream and encode the character of a block basis. Furthermore, the existence of various method for block padding makes the coding operation even more difficult. For this reason, the InputCipherclass provides the necessary method to code or decode an input stream in various mode of operations.

Input cipher mode
The InputCipherclass is an input stream that binds an input stream with a cipher. The class acts like an input stream, read the character from the bounded input stream and encode or decode them from the bended cipher. The InputCipherdefines several modes of operations. In electronic codebook modeor ECB, the character are encoded in a block basis. In cipher block chainingmode, the block are encoded by doing an XOR operation with the previous block. Other modes are also available such like cipher feedback modeand output feedback mode.

Creating an input cipher
By default an input cipher is created with a cipher object. Eventually, an input stream and/or the input mode can be specified at the object construction.

In this example, the input cipher is created in ECB mode. The input stream is later associated with the set-ismethod.

Input cipher operation
The InputCipherclass operates with one or several input streams. The set-ismethod sets the input stream. Read operation can be made with the help of the valid-ppredicate.

while (ic:valid-p) (os:write (ic:read))

Since the InputCipheroperates like an input stream, the stream can be read as long as the valid-ppredicate returns true. Note that the InputCiphermanages automatically the padding operations with the mode associated with the block cipher.

Asymmetric cipher
A public cipher is an object that encodes an input stream with a asymmetric cipher bound to a public and secret key. In theory, there is no difference between a block cipher and a public cipher. Furthermore, the interface provided by the engine is the same for both objects.

Public cipher
A public cipher is an asymmetric stream cipher which operates with an asymmetric key. The main difference between a block cipher and a public cipher is the key nature as well as the encoded block size. With an asymmetric cipher, the size of the message to encode is generally not the same as the encoded block, because a message padding operation must occurs for each message block.

trans count (cipher:stream os is)

The streammethod returns the number of characters that have been encoded. Like the block cipher, the streammethod encodes an input stream or a buffer object. The number of encoded bytes is returned by the method.

Creating a public cipher
A PublicCipherobject can be created with a cipher constructor. The RSAasymmetric cipher is the typical example of public cipher. It is created by binding a RSA key to it. For security reasons, the key size must be large enough, typically with a size of at lease 1024 bits.

A block cipher can be created with a key and eventually a reverse flag. Additional constructors are available to support various padding mode. Such padding mode depends on the cipher type. For example, the RSA cipher supports the ISO 18033-2 padding mode with a KDF1 or KDF2 object. Such constructor requires a hasher object as well.

Public cipher padding mode
Like any cipher, a padding mode can be associated with the cipher. The set-padding-modemethod can be used to set or change the padding mode. Depending on the padding mode type, additional objects might be needed at construction.

Cipher

Padding mode

Default

RSA

PKCS 1.5, PKCS 2.1, ISO/IEC 18033-2

PKCS 1.5

The default padding mode depends on the cipher type. For RSA, the default padding mode is set to PKCS 1.5 for compatibility reason.

Signature objects
A digital signature is a unique representation, supposedly non forgeable, designed to authenticate a document, in whatever form it is represented. For example, a signature is used to sign a certificate which is used during the process of establish a secured connection over the Internet. A signature can also be used to sign a courrieror keys as it is in the Openssh protocol. Digital signatures come into several flavors eventually associated with the signed document. Sometimes, the signature acts as a container and permits to retrieve the document itself. Whatever the method, the principle remains the same. As of today technology, there are two standards used to sign document as indicated below.

Standard

Name

DSS

Digital Signature Standard

RSA

RSA based signature

Signer and signature objects
The process of generating a signature is done with the help of a Signerobject. A signer object is a generic object, similar in functionality to the hasher object. The result produced by a signer object is a Signatureobject which holds the generated signature.

Signature key
The process of generating a signature often requires the use of a key. Such key can be generated with the help of the Keyobject. The nature of the key will depend on the target signature. The following table is a resume of the supported keys.

Standard

Key

Signer

DSS

KDSA

Dsa

In the case of DSS, a key can be generated automatically, although this process is time consuming. The default key size is 1024 bits.

Creating a signer
A Signerobject is created with a particular signature object such like DSA. The Dsaobject is a signer object that implements the Digital Signature Algorithmas specified by the Digital Signature Standard (DSS)in FIPS-PUB 186-3.

Hasher
The Hasherclass is a base class that is used to build a message hash. The hash result is stored in an array of bytes and can be retrieved byte by byte or as a formatted printable string. This class does not have a constructor.

hash-p -> Boolean (String)
The hash-ppredicate returns true if the string argument is potentially a hash value. It is not possible, with our current technology, to reverse a hash value to one or several representations, nor it is possible to assert that such value exists.

get-byte -> Byte (Integer)
The get-bytemethod returns the hash byte value by index. The argument is the byte index which must be in the range of the hash result length.

compute -> String (Literal|Buffer|InputStream)
The computemethod computes the hash value from a string, a buffer or an input stream. The method returns a string representation of the result hash value. When the argument is a buffer object or an input stream, the characters are consumed from the object.

derive -> String (String)
The derivemethod computes the hash value from an octet string which is converted before the hash computation. The method returns a string representation of the result hash value.

Sha512 (Integer)
The Sha512constructor creates a SHA-512 hashing object with a result length. The argument is the hasher result length that must be less or equal to the hasher length.

Key
The Keyclass is an original class used to store a particular key or to generate one. A key is designed to operate with a variety of cipher that can be either symmetric or asymmetric. In the symmetric case, the key is generally an array of bytes. Asymmetric key are generally stored in the form of number list that can be computed or loaded by value. By default, a random 128 bit symmetric key is created.

Predicate

key-p

Inheritance

Object

Constructors

Key (none)
The Keyconstructor creates a default cipher key. The key is generated with random bytes and is 128 bits long.

Key (String)
The Keyconstructor creates a symmetric key from an octet string. The octet string argument determines the size of the key. The octet string argument is compatible with the string obtained from the formatmethod.

Key (Item)
The Keyconstructor creates a key by type. If the key type is KSYM, a symmetric 128 bytes random key is generated. If the key type is KRSA, a 1024 bits RSA random key is generated.

Key (Item Integer|String|Vector)
The Keyconstructor creates a key by type. The first argument is the key type to generate. The second argument is either the key size, the key octet string or the key byte values. In the first form, an integer argument specifies the key size in bytes or bits depending on the key nature. In the second form, a string is used as octet string to represent the key. In the third form, a vector of byte values can be used to load the key.

Constants

KSYM
The KSYMconstant indicates that the key is a symmetric key.

KRSA
The KRSAconstant indicates that the key is a asymmetric RSA key.

KMAC
The KMACconstant indicates that the key is a message authentication (MAC) key.

RSA-MODULUS
The RSA-MODULUSconstant corresponds to the RSA modulus value.

RSA-PUBLIC-EXPONENT
The RSA-PUBLIC-EXPONENTconstant corresponds to the RSA public exponent value which is generally 65537.

RSA-SECRET-EXPONENT
The RSA-SECRET-EXPONENTconstant corresponds to the RSA secret exponent value.

Methods

get-byte -> Byte (Integer)
The get-bytemethod returns a key byte value by index. The index must be in the key range or an exception is raised. This method is primarily used with symmetric key.

get-type -> Item (none)
The get-typemethod returns the key type in the form of an item object.

format -> String (none|Item)
The formatmethod returns a string representation of the key. In the first form, without argument, the key is returned as an octet string if possible. In the second form, the key value is returned as an octet string based on the key element to access.

get-relatif-key -> Relatif (Item)
The get-relatif-keymethod returns a relatif representation of a key element. This method is well suited for asymmetric key. The key value is returned as a relatif based on the key element to access.

Kdf
The Kdfclass is an abstract class used to model key derivation function. The class provides only a byte buffer which can be accessed by index. In the key derivation functions land, there are numerous standards, such like PKCS 2.1, IEEE P1363-2000, ISO/IEC 18033-2. All of these standards have sometimes conflicting definitions.

Predicate

kdf-p

Inheritance

Nameable

Methods

reset -> none (none)
The resetmethod reset the internal state of the kdf object.

Kdf1
The Kdf1class is a hashed key derivation function class that implements the KDF1 specification as defined by ISO/IEC 18033-2. The class is strictly equivalent to the mask generation function (MGF1) defined in PKCS 2.1. On the other hand, this implementation does not conform to the KDF1 specification of IEEE 1363-2000 which is somehow rather bizarre. The class operates in theory with any type of hasher object as long as the octet string is not too long.

Predicate

kdf1-p

Inheritance

Hkdf

Constructors

Kdf1 (Hasher Integer)
The Kdf1constructor creates a KDF1 key derivation function object. The first argument is the hasher object to bind and the second argument is the kdf size.

Kdf2
The Kdf2class is a hashed key derivation function class that implements the KDF2 specification as defined by ISO/IEC 18033-2. The class is strictly equivalent to the key function derivation (KDF1) except that the internal counter runs from 1 to k instead of 0 to k-1. The class operates in theory with any type of hasher object as long as the octet string is not too long.

Predicate

kdf2-p

Inheritance

Hkdf

Constructors

Kdf2 (Hasher Integer)
The Kdf2constructor creates a KDF2 key derivation function object. The first argument is the hasher object to bind and the second argument is the kdf size.

Cipher
The Cipherclass is a base class that is used to implement a cipher. A cipher is used to encrypt or decrypt a message. There are basically two types of ciphers, namely symmetric cipher and asymmetric cipher. For the base class operation, only the cipher name and key is needed. A reverse flag controls whether or not an encryption operation must be reversed. A reset method can also be used to reset the internal cipher state.

Predicate

cipher-p

Inheritance

Nameable

Methods

reset -> none (none)
The resetmethod reset the cipher internal state.

stream -> Integer (OutputStream InputStream)
The streammethod process an input stream and write into an output stream. The method returns the number of character processed. The first argument is the output stream used to write the coded characters. The second argument is the input stream used to read the characters.

set-key -> none (Key)
The set-keymethod sets the cipher key. The first argument is the key to set.

get-key -> Key (none)
The get-keymethod returns the cipher key.

set-reverse -> none (Boolean)
The set-reversemethod sets the cipher reverse flag. The first argument is the flag to set. If the flag is true, the cipher operates in reverse mode. If the flag is false, the cipher operates in direct mode.

get-reverse -> Boolean (none)
The get-reversemethod returns the cipher reverse flag. If the flag is true, the cipher operates in reverse mode. If the flag is false, the cipher operates in direct mode.

BlockCipher
The BlockCipherclass is an abstract class that is used to implement a symmetric block cipher. By default the cipher operates in encryption mode. When the reverse flag is set, the decryption mode is activated. For a block cipher, a block size controls the cipher operations. The class also defines the constants that control the block padding with the associated methods.

Predicate

block-cipher-p

Inheritance

Cipher

Constants

PAD-NONE
The PAD-NONEconstant indicates that the block should not be padded.

PAD-BIT-MODE
The PAD-BITconstant indicates that the block should be padded in bit mode.

PAD-ANSI-X923
The PAD-ANSI-X923constant indicates that the block should be padded according to ANSI X 923 standard.

PAD-NIST-800
The PAD-NIST-800constant indicates that the block should be padded according to NIST 800-38A recommendations. This is the default mode.

InputCipher
The InputCipherclass is an stream interface that can stream out an input stream from a cipher. In other word, an input stream is read and block are encoded as long as the input stream read characters. If the cipher is nil, the input cipher simply read the input stream and is therefore transparent. The class acts like an input stream, read the character from the bounded input stream and encode or decode them from the bounded cipher. The InputCipherdefines several modes of operations. In electronic codebook modeor ECB, the character are encoded in a block basis. In cipher block chainingmode, the block are encoded by doing an XOR operation with the previous block. Other modes such like cipher feedback modeand output feedback modeare also defined.

Predicate

input-cipher-p

Inheritance

Input

Constructors

InputCipher (Cipher)
The InputCipherconstructor creates an input cipher with a cipher object. The first argument is the cipher to used for processing.

InputCipher (Cipher Input)
The InputCipherconstructor creates an input cipher with a cipher object and an input stream. The first argument is the cipher to used for processing. The second argument is the input stream object used for the character reading.

InputCipher (Cipher InputStream Item)
The InputCipherconstructor creates an input cipher with a cipher object, an input stream and a mode. The first argument is the cipher to used for processing. The second argument is the input stream object used for the character reading. The third argument is the input cipher mode which can be either ECB, CBC, CFB or OFB.

Constants

ECB
The ECBconstant indicates that the input cipher is to operate in electronic codebookmode. This mode is the default mode.

CBC
The CBCconstant indicates that the input cipher is to operate in cipher chaining blockmode.

CFB
The CFBconstant indicates that the input cipher is to operate in cipher feedback blockmode.

OFB
The OFBconstant indicates that the input cipher is to operate in output feedback blockmode.

set-iv -> none (String|Buffer)
The set-ivmethod sets the input cipher initial vector. In the first form, the initial vector is set from an octet string. In the second form, the initial vector is set from a buffer object.

set-is -> none (InputStream)
The set-ismethod sets the input cipher input stream. This method can be used to chain multiple input streams in a unique coding session.

Aes
The Aesclass is a block cipher class that implements the advanced encryption standard(AES), originally known as Rijndael. This is an original implementation that conforms to the standard FIPS PUB 197. It should be noted that the AES standard, unlike Rijndael, defines a fixed block size of 16 bytes (4 words) and 3 keys sizes (128, 192, 256).

Predicate

aes-p

Inheritance

BlockCipher

Constructors

Aes (Key)
The Aesconstructor creates a direct cipher with a key. The first argument is the key used by the cipher.

Aes (Key Boolean)
The Aesconstructor creates a cipher with a key and a reverse flag. The first argument is the key used by the cipher. The second argument is the reverse flag.

PublicCipher
The PublicCipherclass is an abstract class that is used to implement an asymmetric cipher. An asymmetric cipher or public key cipher is designed to operate with a public key and a secret key. Depending on the use model, the public key might be used to crypt the data, and the secret key to decrypt. The basic assumption around a public cipher is that the secret key cannot be derived from the public key.

Rsa
The Rsaclass is a public cipher class that implements the RSA algorithm as described by PKCS 2.1, RFC 2437 and ISO 18033-2. The class implements also some padding mechanism described in PKCS 1.5, 2.1 and ISO 18033-2. The RSA algorithm is a public cryptographic cipher based on a secret and public keys. The class operates in crypting mode by default and uses the public key to do the encryption while the secret key is used in reverse (decryption) mode. By default, the PKCS 1.5 type 2 padding is used. The ISO RSA-REM1 padding with a key derivation function (KDF1) is equivalent to PKCS 2.1 padding with the mask generation function (MGF1). The ISO RSA-REM1 padding with KDF2 is not described in the PKCS 2.1.

Rsa (Key)
The Rsaconstructor creates a RSA public cipher by binding the key argument.

Rsa (Key Boolean)
The Rsaconstructor creates a RSA public cipher by binding the key argument and the reverse flag. The first argument is the key to bind. The second argument is the reverse flag to set.

Rsa (Key Hasher String)
The Rsaconstructor creates a RSA public cipher by binding the key argument and OAEP padding objects. The first argument is the key to bind. The second argument is hasher object to use with the OAEP padding mode. The third argument is an optional label to be used by the KDF object.

Constants

PAD-PKCS-11
The PAD-PKCS-11constant indicates that the PKCS 1.5 type 1 block should be used to pad the message.

PAD-PKCS-12
The PAD-PKCS-12constant indicates that the PKCS 1.5 type 3 block should be used to pad the message.

PAD-OAEP-K1
The PAD-OAEP-K1constant indicates that the ISO/IEC 18033-2 OAEP with KDF1 should be used to pad the message.

PAD-OAEP-K2
The PAD-OAEP-K2constant indicates that the ISO/IEC 18033-2 OAEP with KDF2 should be used to pad the message.

Methods

get-hasher -> Hasher (none)
The get-hashermethod returns the hasher object used by the OAEP padding mode.

set-hasher -> none (Hasher)
The set-hashermethod sets the hasher object used by the OAEP padding mode.

compute -> Signature (Literal|Buffer|InputStream)
The computemethod computes the signature from a string, a buffer or an input stream. The method returns a signature object. When the argument is a buffer object or an input stream, the characters are consumed from the object.

derive -> Signature (String)
The derivemethod computes the signature from an octet string which is converted before the signature computation. The method returns a signature object.

Signature
The Signatureclass is a container class designed to store a message signature. The signature object is produced by a signing process, implemented in the form of a digital signature algorithm such like RSA or DSA.

Predicate

signature-p

Inheritance

Object

Constructors

Signature (none)
The Signatureconstructor creates an empty signature.

Constants

NIL
The NILconstant indicates that the signature is a null signature.

DSA
The DSAconstant indicates that the signature is conforming to DSS.

DSA-S-COMPONENT
The DSA-S-COMPONENTconstant corresponds to the DSA S component value.

DSA-R-COMPONENT
The DSA-R-COMPONENTconstant corresponds to the DSA R component value.

Dsa
The Dsaclass is an original implementation of the Digital Signature Standard (DSS) as published in FIPS PUB 186-3. This class implements the Digital Signature Algorithm (DSA) with an approved key length of 1024, 2048 and 3072 bits with a 160, 224 and 256 bits hash function which is part of the SHA family.

Predicate

dsa-p

Inheritance

Signer

Constructors

Dsa (none)
The Dsaconstructor creates a signer object with a default DSA key.

Dsa (Key)
The Dsaconstructor creates a signer object with a DSA key as its argument.

Dsa (Key Relatif)
The Dsaconstructor creates a signer object with a DSA key as its first argument and a fixed kargument as specified by DSS.